A-B line (A-B chokusen)

The A-B line is one of the indicators used in managing moromi (fermentation mash) in sake brewing. It is a straight-line graph showing the relationship between alcohol content (A) and Baume degree (B). Baume degree is a measure of concentration based on the specific gravity of a liquid, and it is important when evaluating how far fermentation has progressed in sake brewing. By using the A-B line, the fermentation state of the moromi can be grasped visually, which serves as a reference for appropriate management and adjustment. The slope and position of this line indicate changes in sugar content and the progress of fermentation during the fermentation process, providing information useful for quality control in sake brewing.